Websites that provide electronic services receive input from client machines in the form of click streams. For example, a website hosting an online banking service may receive a stream of clicks over the course of an online banking session. A “click” represents a request to access content from a web site or to process data, such as may occur when a user points to and clicks on a link. “Clicks” are not limited to pointer clicks, however, but may include any requests from a client machine to a webserver. A “click stream” or “stream of clicks” is a sequence of clicks over time.
Occasionally, a click stream may exhibit temporally periodic behavior, e.g., a click stream may exhibit a click once per second to reflect requests made once per second from a client machine. Conventional approaches to detecting periodicity in click streams involve verifying whether clicks in the click stream are evenly spaced in time.